An integrity control system for retinal images based on watermarking

Multimedia Tools and Applications - In telemedicine, images may possibly be tailored deliberately or unintentionally as this transmission may occur all the way through vulnerable networks. Prior to...     

Molecular Dynamics Simulations of a Catalytic Multivalent Peptide–Nanoparticle Complex

Molecular modeling of a supramolecular catalytic system is conducted resulting from the assembling between a small peptide and the surface of cationic self-assembled monolayers on gold nanoparticles, through a multiscale iterative approach including atomistic force field development, flexible docking with Brownian Dynamics and µs-long Molecular Dynamics simulations. Self-assembly is a prerequisite for the catalysis, since the catalytic peptides do not display any activity in the absence of the gold nanocluster. Atomistic simulations reveal details of the association dynamics as regulated by defined conformational changes of the peptide due to peptide length and sequence. Our results show the importance of a rational design of the peptide to enhance the catalytic activity of peptide–nanoparticle conjugates and present a viable computational approach toward the design of enzyme mimics having a complex structure–function relationship, for technological and nanomedical applications.     

Effect of shearing history on stress wave velocities of sands observed in triaxial compression tests

For the accurate design of geotechnical structures subjected to static and dynamic loadings, precise estimation of elastic wave velocities and hence, small strain stiffness of soil is essential. However, the interpretation of elastic wave velocities propagating in deformed/sheared soil has not been comprehensively explored. In this research, shear (V_s) and compression wave velocity (V_p) measurements have been undertaken on three kinds of uniformly graded sands during drained triaxial compression by keeping minor principal stress constant. Planar piezoelectric transducers have been used to overcome the limitations associated with the more commonly used bender elements, such as distortion of transducers during specimen shearing. This technical note reveals that the increase of major principal stress in the wave propagation direction has a more significant influence on V_p in comparison to V_s. The axial strain (ε_a) at which peak V_s is noted is comparable to the ε_a at which specimen dilation or phase transformation takes place. The V_s values show a substantial drop after phase transformation, although there is an increase in the mean stress level. However, V_p increases even after specimen dilation takes place, and it is the major principal stress that dictates its evolution during triaxial compression. Moreover, for a given material and initial stress level, elastic wave velocities of specimens prepared at different initial densities approach one another during shearing and later merge at a large ε_a.     

Impact of Left Side Back Gate Misalignment Effect in an Analytical Tunneling Current Modeling of an Ultrathin Asymmetric DG TFET

Silicon - This paper exhibits a detailed explanation of an analytical band to band tunneling current model with gate misalignment effect for an ultrathin n type Asymmetric DG TFET considering...     

Coalition Formation for Multi-Robot Task Allocation via Correlation Clustering

Abstract

The complexity of a vast number of real world tasks provides a great challenge for the currently available robots due to their limited capabilities. Thus, multiple robots would need to form coalitions for the completion of such tasks. In this paper, we examine the multi-robot coalition formation problem for task allocation where a group of robots needs to be allocated to a set of tasks. Our approach for this problem is to use a correlation clustering technique enabling similar robots to form coalitions. The algorithm presented in this paper is fast and scales better in comparison to two existing algorithms.     

Microstructure correlated electrical conductivity of Manganese alloyed nanocrystalline cubic zirconia synthesized by mechanical alloying

Fully stabilized cubic (c) ZrO₂ phase has been synthesized by mechanical alloying (MA) the stoichiometric powder mixture of elemental Mn (5–20 mol%) and monoclinic (m) ZrO₂ at room temperature. XPS study reveals that major part of metallic Mn is ionized to Mn²⁺ oxidation state during MA. Mn-alloyed c-ZrO₂ nanoparticles with ～18 nm particle size have been synthesized within 10 h of MA. Microstructures of the compounds have been precisely evaluated by analyzing the X-ray powder diffraction patterns employing Rietveld refinement and transmission electron microscopy images. A decrease in lattice parameter from 5.11 Å to 5.09 Å is correlated with an increase in oxygen vacancy from 14% to 26% with increasing Mn concentrations. Elemental compositions in the compounds are obtained from electron probe microanalysis. The role of Mn alloying in the polymorphic phase transformation (m → c) has been established with changes in structure and microstructure parameters. Electrical conductivities of all c-ZrO₂ compounds are measured in the temperature range 350–550 °C. Grain and grain boundary contributions to total conductivity are calculated from frequency dependent real and imaginary impedance. Conductivity of Mn alloyed c-ZrO₂ increases with increasing temperature and Mn concentrations. Electrical transport mechanism in the compound is studied by impedance and modulus spectroscopy. The relaxation frequency is found to be temperature, microstructure and composition dependent.     

Evolutionary algorithms for optimal synthesis of thinned multiple concentric circular array antenna with constraints

ABSTRACT

The novel implementation of three evolutionary optimisation algorithms, namely quantum particle swarm optimisation (QPSO), teaching-learning based optimisation (TLBO) and symbiotic organism search (SOS) for thinning of multiple concentric circular array antenna with isotropic array elements for the simultaneous optimisation of the sidelobe levels (SLLs) as well as peak directivity is presented in this work. The performance studies as cases 1 and 2 are made with two control parameters: interring radii and number of switched ‘on–off’ elements in each ring. The comparative study of the three algorithms has been carried out using common parameters. Finally, experimental results show that case 2 outperforms case 1 with regard to SLL and directivity. Apart from this, the results of SOS have been shown to be better than the other two state of art meta-heuristic optimisation after comparing their effectiveness based on SLL, peak directivity, mean value, and standard deviation along with best cost. For statistical validation of both cases, t-test has been done for testing the stability of SOS over QPSO and TLBO.     

Design and analysis of perforated MEMS resonator

Microsystem Technologies - In this paper, we have designed an optimal design of microelectromechanical (MEMS) resonator. The paper explains the idea of suitable design, modeling and optimization of...     

Nanoliposomal encapsulation of chia oil for sustained delivery of α-linolenic acid

Chia oil is a popular source of ω-3 fatty acids, typically α-linolenic acid. This study reports the encapsulation of chia oil in nanoliposome to protect ω-3 fatty acids and to obtain a sustained release of chia oil during digestion. Nanoliposomal encapsulation was carried out using solvent evaporation, followed by sonication. The encapsulation process was conducted using different lipid contents, with different concentrations of soy phosphatidylcholine (S), Tween 80 (T) and volumes of the aqueous phase. The maximum encapsulation efficiency was found to be 88.31%, and the average particle size was 49.25 nm; a moderate repulsion among the particles was observed. Differential scanning calorimetry study revealed enhanced thermal stability of chia oil in nanoliposomes. A negligible release (3.39%) of encapsulated chia oil was observed in the simulated gastric fluid, and a 74.72% sustained release was recorded in the simulated intestinal fluid. This formulation can be a suitable supplement of ω-3 fatty acids for food and therapeutic applications.